Aqueous calcium hypochlorite mixtures are used for various cleaning and disinfecting purposes, including germ control in swimming pools and disinfecting of toilet bowls and tanks. In many of these uses, it is helpful to include a color indicator in the hypochlorite mixture which will indicate when the hypochlorite concentration is reduced to a level such that the cleaning/disinfecting properties become ineffective or only marginally effective.
Systems for indicating color incorporated in dispensers are disclosed in U.S. Pat. No. 4,171,546 issued to Dirksing, U.S. Pat. No. 4,200,606 issued to Kitko, U.S. Pat. No. 4,208,747 issued to Dirksing, and U.S. Pat. No. 4,216,027 issued to Wages. The Kitko '606 disclosure discusses a system wherein a dye is provided for giving a persistent color to the bowl water between flushes of the toilet. The objective is to assure a consumer that the bowl is being sanitized and means are provided to indicate the time when the disinfectant needs to be replaced. This is accomplished by controlling the quantities of Ca(OCl).sub.2 and color indicator, contained in separate chambers, so that the source of the color indicator is exhausted at about the time the calcium hypochlorite is nearly exhausted.
Other toilet tank dispensers for calcium hypochlorite mixtures have no provisions for indicating by means of color. For example, U.S. Pat. No. 3,837,017 issued to McDuffee discloses a passive system for cleaning toilet bowls wherein a container for calcium hypochlorite is located within a water tank associated with the bowl. A small diameter opening is provided within the top wall of the container to provide exposure to water in the tank so that the compound will be dissolved in the water and thereby delivered to the bowl when the toilet is flushed. An amount of inert particles, such as stone, may be included in the container to cooperate with the small diameter opening for purposes of limiting the rate of removal of the compound from within the container.
U.S. Pat. No. 4,435,857 to Meloy, Meloy application Ser. No. 385,454, filed June 7, 1982, Meloy application Ser. No. 545,883 filed Oct. 27, 1983, Meloy application. Ser. No. 545,876 filed Oct. 27, 1983, and Meloy application. Ser. No. 565,720, incorporated herein by reference, disclose various indicator systems wherein hypochlorite or the like essentially bleaches out the color capability of a selected dye for as long as the hypochlorite is present in sufficient amounts. When the hypochlorite amounts are at or near exhaustion, the dye will provide a color signal indicating that a new supply of hypochlorite is required.